I have only auditioned the 2.5B3 amp along with the BP-17cubed preamp. I compared these to my 4B2 amp/BP-26 preamp/MPS2 external power supply that I currently have.
My current components are powerful and musical but lack some detail which obscures my ability to really follow the song more naturally. The interplay of the different instruments, vocalists and background vocalists has more clarity and depth to it which really gets you enjoying some of your recordings that you thought were "bad" recordings. Often times these aren't "bad" recordings, they are more often layered, complex recordings that are more difficult for the gear to render the meanings the right way.